Floatless carburetor



March 28, 1961 T. M. BALL 2,977,099

FLOATLESS CARBURETOR Filed May 26, 1959 INVENTOR. 7%&77r/\ s' )7, 34/].

BY ww ##W United States PatentO FLOATLESS CARBURETOR A Thomas M. Ball, Bloomfield Hills, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware 7 I Filed May 26, 1959, Ser.'No. 815,845

13 Claims. (Cl. 261-36) This invention relates to a carburetor for an internal combustion engine and has for an important object the provision of an improved floatless carburetor of particu- 2,977,099 Patented .Mar. 28, 1961 ice and tilting of the vehicle has a minimum effect in varying the'fuel head and thus thefuel supply to the various induction conduits of a multiple barrel carburetor.

Other objects of this invention will appear in the following description and appended claims, reference being had to the, accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts invthe several views.

lar simple, compact, and economical construction characterized by improved operating efliciency for usein an automotive vehicle.

Another object is to provide such a carburetor having a fuel bowl in communication with a fuel supply and having an overflow weir defining an acceleration pump chamber within the fuel bowl, whereby excess fuel supplied to the bowl overflows the weir to maintain the fuel in the bowl at a constant level determined by the effective height of the weir. 7

Another object is to provide such a construction wherein the acceleration pump chamber has a lower cylindrical portion containing a reciprocable plunger adapted to be actuated by conventional means such as a linkage with an accelerator pedal. A fuel connection between the bowl and cylinder supplies fuel to the latter below the plunger. A second fuel connection with the cylinder at the underside of the plunger supplies fuel to the engine, 'as for example by way of the usual air inlet inductionconduit, upon downward movement of the plunger. Excess fuel overflowing the weir is returned to the fuel tank or 'to the inlet side of a fuel pump by means of a return fuel conduit in communication with the chamber above the plunger. 3

Another object is to provide such a construction in a multiple barrel carburetor wherein the acceleration pump is arranged centrally within the fuel bowl and wherein a plurality of air inlet induction or fuel-air mixing conduits are arranged adjacent the fuel bowl around its periphery. By virtue of the foregoing, a particularly compact and efiicient carburetor construction is achieved which avoids the requirement of the usual float operated inlet valve otherwise required to maintain a constant fuel level in the fuel bowl. Also by arranging the acceleration pump within the chamber defined by the overflow weir, not only are economy and compactness of structure achieved, but the size of the fuel bowl is feasibly minimized' and an improved carburetor design is enabled which achieves uniform fuel distribution from either the fuel bowl' or the acceleration pump-to all of the induction conduits of a multiple barrel carburetor. Reducing the volume and surface area of fuel in'the fuel bowl assures a continuous flow 'of fresh and comparatively cool fuel through the bowl during hot driving conditions and reduces fuel vapor formation, in the fuel bowl. Unless the fuel vapor is bled by a return line to the. fuel tank or lost to the atmosphere, the desired fuelair ratio that would otherwise be obtained by the usual fuel metering system tends to vary. Among other advantages of the foregoing structure, the comparatively small centrally located fuel bowlassures its rapid refill and starting of the engine after the latter has been idle for sufiicient time to allow evaporation of the fuelfrom the fuel bowl.

Also sloshing of fuel in the comparatively small fuel bowl is reduced during sudden changes in velocity or direction,

Figure lis a fragmentary schematic vertical sectional view through a carburetor structure embodying the present invention. v

Figure 2 is a reduced transverse'sectional view'taken in the direction of the arrows substantially along the line 22 .of Figure 1. a i

Figure 3 is a view similar to Figure 2 but showing a two-barrel carburetor.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways.

I Also it is to be understood thatthe phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to the drawings, a carburetor body is illustrated comprising an upper air horn casting 8 having a customary choke valve blade 9 mounted therein on a pivotal shaft 10 and secured to the latter by screws 11. The carburetor body also comprises a lowerventuri portion '12 having in the present instance .an'integral fuel bowl casting 13 containing a generally annular fuel reservoir or bowl 14 enclosing.acoaxial cylindrical acceleration fuel pumping chamber 15. Also integral withthe upper horn casting 10 is a fuel bowl cover 16 suitably secured to the lower casting 13 by screws not shown. The lower casting 12 is formed with a venturi portion 17 and contains the customary throttle valve blade 18 in an integral lower throttle body portion.

A fuel'inlet conduit 19 is connected with an upper portion of the fuel bowl casting 13 so as'to communicate .with the fuel bowl 14. A fuel return conduit 20 communicates with the interior of the chamber 15 at an intermediate location and extends outwardly through the casting 13 so as to drain excess fuel which enters the chamber 14 via conduit 19 and overflows the upper edge 21 of the cylindrical chamber 15. Accordingly the chamber 15 comprises an overflow weir which limits.the fuel within the bowl 14 to the level of the upper surface, 21. Reciprocable axially within cylinder 15 is a cylindrical plunger 22 normally urged downwardly by a coil spring 23 under compression between plunger 22 and the under side of cover 16 and coiled around a plunger shaft 24.

The latter is loosely secured asdescribed below to a bracket 25 which in turnis rigidly secured to the upper portion 26 of a dog-leg lever. The latter has a lower portion 27 extending downwardly toward throttle valve 18 preferably at a location exteriorlyof the air induction, conduit, comprising the airhorn and venturi castings 8 and 12 respectively, so as not to interferewith air fiow to the throttle valve 18. The member 27 is pivotally connected at its lower end at 31 to a. link 28 which in turn is pivotally connected at 32 to the outer end of a crank arm'30' of valve 18. The pivotal portion of crank arm 30 is suitably keyed to an exterior extension of a pivotal shaft 33-.which extends transversely through the throttle body portionof casting 12 and is secured to valve blade 18 by screws 34.

' Fuel is supplied to the lower portion of chamber 15 belowplunger 22 by conduit .35 in communication with fuel bowl ,14. A ball check valve 36 seated at thelower aeraooo latter is normally urged by spring '39 to a position closing conduit 37, thereby to'preve'nt air from entering the lower portion of chamberlS during the upward intake stroke of plu1'1ger22. Conduit 37 extends from its lower end in communication with chamber below plunger 22 and discharges'via an acceleration fuel nozzle 40 into the aforesaid induction "conduit adjacent the region of venturi 17. g

It is apparent that upon clockwise pivoting of crank 'arm 30 to thelow'er positionillustrated in "phantom, Figure 1, as for example by operation of the customary'foot pedal controlled accelerator rod '41, throttle valve 18 will be opened to increase the fuel-air flowjto the engine. Conjointly the dog-leg lever 26, 27 will be pulled downwardly by link 28. The upper'en'd of. plunger 24 extends freely slidably through an oversize hole 42 in bracket 25 in order to enable downward movement of the latter independently'of plunger 24. Thus spring 23 under compression as aforesaid is enabled to force plunger 22 downwardly and effect the discharge of a surge of acceleration fuel to nozzle 40 through conduit 37. Upon actuation of 'rod 41 to cause counterclockwise closing movement of throttle valve 18, dog-leg lever'26, 27 is moved upward to the position illustraed in Figure 1, plunger 24 is raised 'against the tension of spring 23, and fuel is drawn into chamber 15 below plunger'22 via conduit 35 and check valve 36, The upper-fend of plunger 24 is enlarged'at 29 -above hole 42, so that'npward movement of bracket 25 .pulls plunger 24upward. The main fuel supply is delivered to the enginejin accordance with customary practice by COndUitJ44 opening {at its lower end through a metering orifice '45 into'tlie lower portion of fuel well 14 and discharging 'atits upper end through 'a' main fuel supply nozzle'46 into the throat of the venturi 17.

By virtue of the structure described, including the fuel bowl 14 arranged as shown 'in cooperation with the acceleration pump located centrally within the fuel bowl and comprising the 'overflo'w'w'eir, an improved effective carburetor design is rendered feasible fora multiple barrel carburetor, 'as illustrated in Figures 2' and 3. Also the customary leathersealing cup 43 at the lower end of plunger 22 is maintained in a moist condition by the fuel and is always ready'for instant operation.

Figure 1 may be "considered 'to be somewhat schematic vertical sectional view through the fuel bowl, acceleration pump, overflow we'ir,'and one of the induction conduits illustrated in either Figure 2 or Figure 3. Thus in the four-barrel carburetor construction, the four induction conduits including the venturi portions 17 will be arranged symmetrically around the periphery of the fuel bowl. The fuel supply conduits 37 and 44 to each induction passage are the same length as the corresponding conduits for the other induction passages, and asymmetrical fuel supply system is readily' achieved. 'The two-barrel carburetorcan have one of each of the 'barrels or induction conduits arranged at'diametrically opposed sides of the fuel bowl, or'may comprise essentially one-half of a four barrel carburetor as illustrated.

In addition to 'th'e economyand compactness ofdesign illustrated, itis' apparent thatthe central arrangement ofthe fuel bowl, particularlyin the four barrel' construction of Figure 2, minimizes the eifect'of acceleration or rapid tilting or turning of .the vehicle on "the fuel pressure headffor the various fuel supply conduits is concerned. Thus" a moreluniform fuel supply is obtained under varying external conditions.

I claim: I I v V 1. In a carburetor-for an internal combustionflen gine, a fuel bowl in communication" with asource of fu eh f an overflow chamber, means for maintaining the fuel in said bowl at a predetermined level comprising an overflow weir separating said bowl and chamber, said chamber being adapted to receive excess fuel overflowing said weir from said bowl after the fuel in said bowl attains said predetermined level, fuel pumping means defined in part by said chamber, means for supplying fuel to said pumping means, means for conducting fuel from said pumping means to said engine upon actuation of said pumping means, means operatively connected with said pumping means to actuate the latter, and'fuel'return means in communication with said chamber to drain fuel therefrom upon overflow of fuel from said bowl into said chamber.

2. In a carburetor for an internal combustion engine, a fuel bowl in communication with a source of fuel, means for maintaining the fuel in'said bowl at a predetermined level comprising an overflow weir in said bowl defining a chamber therein adapted to receive excess fuel overflowing said weir from said bowl after the fuel in said bowl attains said predetermined level, fuel pumping means in a lower portion of said chamber, means for supplying fuel to said pumping means, means for conducting fuel from said pumping means to said engine upon actuation of said pumping means, means operatively connected with said pumping means to actuate the latter, and fuel return means in communication with said chamber at a location above said lower portion to drain the overflow of fuel from said bowl into said chamber.

3. In a carburetor for an internal combustion engine, a fuel bowl in communication with a source of fuel, means for maintaining the fuel in said bowl at a predetermined level comprising an overflow weir in said bowl defining a fuel pumping chamber in said bowl adapted to receive excess fuel overflowing said weir-from said bowl after the fuel insaid bowl attains said predetermined level, an acceleration fuel pumping mechanism in a portion of said chamber, means for supplying fuel 'to s'aidportion, means for conducting fuel from said portion to said engine upon actuation of said pumping mechanism, means operatively connected with said pumping mechanism to actuate the latter, and fuel return means in communication with said chamber to drain said excess Ifuel therefrom upon overflow of fuel from said bowl into means for maintaining the fuel in said bowl at a predetermined level comprising an overflow weir in said b'owl defining a chamber therein adapted to receive excess'fuel overflowing said weir from said bowl after the fuel in said bowl attains said predetermined level, fuel pumping means in a lower portion of said chamber in communication with said excess fuel, means connecting said bowl and pumping means for supplying fuel to the latter, means for conducting fuel from said pumping means to said engine upon actuation of said pumping means, means operatively connected with said pumpingmeans to actuate the latter, and fuel return means in communication with said chamber at a location above said pumping means to drain said excess fuel upon overflow of fuel from said bowl into'said chamber.

5. In a carburetor for an internal combustion engine,

-a. fuel bowl in communication with a source of fuel,

means for maintaining the fuel in said bowl at a predetermined level comprising an overfiow weir in'said bowl enclosing a chamber surrounded peripherally by the fuel in said bowl and adapt edto receive excess fuel'overfiowing said weir from'said bowl after the fuel in said bowl "attains said predetermined level, fuel pumping means "in a portion of said chamber, means for supplying fuel to "said portion, means for'conducting fuel from said porjtiou to said engine upon actuation of saidpump'ing means, meansj operatively connected with said pumping 'means to actuate the latter, and fuel return-means in communication with said chamber to drain fuel therefrom upon overflow of fuel from said bowl into said,

chamber.

6. In a multiple barrel carburetor for an internal combustion engine, a fuel bowl in communication with a source of fuel, a plurality of inlet air induction conduits arranged peripherally around said bowl and adjacent thereto, a separate throttle valve in each air inlet conduit, throttle means for actuating said throttle valves, means for maintaining the fuel in said bowl at a predetermined level comprising an overflow weir in said bowl defining a chamber therein located symmetrically with respect to said induction conduits and adapted to receive excess fuel overflowing said weir from said bowl after the fuel in said bowl attains said predetermined level, fuel pumping means in a lower portion of said chamber, means for supplying fuel to said lower portion, means arranged symmetrically with respect to said pumping means for conducting fuel from said lower portion to each of said inlet conduits upon actuation of said pumping means, means operatively connecting said throttle means with said pumping means to actuate the latter conjointly with actuation of said throttle valves, and fuel return means in communication with said chamber at a location above said lower portion to drain fuel therefrom upon overflow of fuel from said bowl into said chamber.

7. In a carburetor for an internal combustion engine, a fuel bowl in communication with a source of fuel, an overflow chamber in said bowl having an upper opening for receiving excess fuel from said bowl when the fuel therein attains a predetermined level, an acceleration fuel pump including a cylinder in a lower portion'of said chamber, a reciprocable fuel pumping plunger in said cylinder exposed to the fuel in said chamber above said lower portion, means connecting said bowl and cylinder for supplying fuel to the latter upon movement of said plunger in one direction, means for conducting fuel from said cylinder to said engine upon movement of said plunger in the opposite direction, means operatively connected with said plunger to actuate the latter, and fuel return means in communication with said chamber at a location above said plunger to drain fuel therefrom upon overflow of fuel from said bowl into said chamber.

8. In a carburetor for an internal combustion engine, an air inlet induction conduit for supplying a fuel-air mixture to said engine, a fuel bowl adjacent said conduit, an overflow chamber arranged centrally within said how] and having an upper opening for receivingexcess fuel from said bowl when the fuel in the latter attains a predetermined level, the lower portion of said chamber being a cylinder, a reciprocable acceleration fuel pumping plunger in said cylinder, means for supplying fuel to said cylinder below said plunger, means for conduct-.-

ing fuel from said cylinder to said air inlet conduit upon overflow cylinder adjacent said bowl having an upper opening for receiving excess fuel from said bowlwhen the fuel in the latter attains a predetermined level, an axially reciprocable fuel pumping plunger in a lower portion of said cylinder, means for supplying fuel to said cylinder below said plunger upon upward movement of said plunger, means for conducting fuel from said cylinder to said engine upon downward movement of said plunger, means operatively connected with said plunger to actuate the latter, and fuel return means in communication with said chamber at a location above said plunger to drain fuel therefrom upon overflow of fuel from said bowl into said chamber.

11. In a carburetor for an internal combustion engine, a fuel bowl in communication with a source of fuel, a vertical overflow cylinder in said bowl surrounded peripherally by the fuel in said bowl and opening upwardly to receive excess fuel from said bowl when the fuel in the latter attains a predetermined level, a vertically reciprocable acceleration fuel pumping plunger in a. lower portion of said cylinder, means connecting said bowl and cylinder for supplying fuel to the latter below said plunger upon upward movement of said plunger, means for conducting fuel from said cylinder to said engine upon downward movement of said plunger, means operatively connected with said plunger to actuate the latter, and fuel return means in communication with said cylinder at a location above said plunger to drain fuel therefrom upon overflow of fuel from said bowl into said cylinder.

12. In a multiple barrel carburetor for an internal combustion engine, a fuel bowl, an overflow chamber arranged centrally within said bowl and having an upper opening for receiving excess fuel from said bowl when the fuel in the latter attains a predetermined level, the lower portion of said chamber being an upwardly opening cylinder,

predetermined actuation of said plunger, means operaa reciprocable acceleration fuel pumping plunger in said cylinder, means for supplying fuel to said cylinder below said plunger, a plurality of air inlet induction conduits for supplying a fuel-air mixture to said'engine and ar ranged adjacent said bowl symmetrically thereto and to said chambena throttle valve in each air inlet conduit, means arranged symmetrically with respect to said cylinder and each air inlet conduit for conducting fuel from said cylinder to each air inlet conduit upon predetermined actuation of said plunger, means for actuating each throttle valve and plunger conjointly, and fuel return means in communication with said chamber at a location above said plunger to drain fuel from said chamber 7 upon overflow of fuel thereinto from said bowl.

13. In a multiple barrel carburetor for an internal comaxially within the other, aplurality of air inlet induction conduits arranged symmetrically aroundtheperiphery of said cylinders and adjacent thereto, a separate throttle 9. In a multiple barrel carburetor for an internal combustion engine, a cylindrical fuel bowl, a plurality of air inletinduction conduits arranged around the periphery cylinder below said plunger, means forconducting fuel from said cylinder to each ofsaid air inlet conduits upon 1 predetermined actuation ofsaid plunger, means operatively connected with said plunger to -actuatethe same, and, 'fuel return means 'in communicationjwith" said cylinder above said plunger to drain. fuel from said-cylinder upon overflow of fuel thereinto fiom said -bowl. g

10; Ina carburetor for an internal combustion engine, 2,846,203 Voss et I valve in each of said air inlet conduits, said overflowgcylincylinder below said plunger, means for conducting fuel 1 from said innermost cylinder to each of said air inlet condu'itsupon predetermined actuation of said plunger, means for actuating said plunger and throttle valves conjointly,

and fuel return means in communication'with said overflow cylinder to drain fuel therefrom upon overflow of, I 7

fuel thereinto from said bowl. 7 References Cited inthe file ofthis patent UNITED STATES PATENTS I 

